Series lamp cutout



March 25, 1952 F/W, GODSEY, JR

SERIES LAMP CUTOUT Filed March 28, 1950 INVENTOR Frqnk W. Godsey,v Jr.

Patented Mar. 25, 1952 UNITED STATES PATENT OFFICE SERIES LAMP CUTOUTFrank W. Godsey, Jr., Pittsburgh, Pa., assigner to Westinghouse ElectricCorporation, East Pittsburgh, Pa., a corporation of PennsylvaniaApplication March 28, 1950, Serial No. 152,419

8 Claims.

My invention relates, generally, to switch desimple, reliable andcompact construction, and

which may be economically manufactured and used.

A more specic object of my invention is to provide a cutout deviceembodying a thermally controlled or released mechanical switch element.

Another object of my invention is to provide l a cutout device `whereinthe short-circuiting or circuit-closing operation is performed by aresilient or fiexible contact element which is released from a normallyopen position to a contact making position in response to apredetermined increase in the temperature of the device resulting fromincreased voltage applied thereto due to lamp failure.

A further object of my invention is to provide a cutout device of thecharacter described wherein the shunting or circuit making operation iseffected by a flexible contact spring normally retained in an openposition by a quantity of solder which is melted to release the contactspring in response to an increase in the operating temperature of thedevice due to the interruption of the series circuit through the lamp.

A still further object of my invention is to provide a cutout device ofthe character described wherein the contact spring is normally held inan open or retracted position by a thermally responsive latch member ordevice which is actuated in response to a predetermined increase intemperature to release the contact spring.

Another object of my invention is to provide a cutout device of thecharacter described wherein the necessary heat to trip or release thecontact spring is produced in the device itself by passing currentthrough a small block or ring of non-linear conducting material.

It is also an object of my invention to provide a cutout device of thiskind which may be reset or readjusted to its normal operating conditionafter it has once operated to short-circuit the lamp.

These and other objects of my invention will be more readily understoodfrom thefollowing detailed description, when considered in conjunctionwith the drawing, in which:

Figure 1 is an elevational view, in section, o a cutout device embodyingthe principal features of my invention;

Fig. 2 is a sectional view taken along lines II-II of Fig. l;

Fig. 3 is an elevational view, in section, of a modification of myinvention; and

Fig. 4 is a sectional view taken along lines IV-IV of Fig. 3. v

In practicing my invention in its preferred form, the cutout device isformed in the usual button or wafer shape and comprises a spacer elementin the form of a block, a pair of blocks', or a ring of fused siliconcarbide clay pressed or held between two metal discs constituting thecontact plates or terminals of the device. The spacer, in whatever formit may take, is of such nature that a recess or cavity is formed in thedevice in which the switch or contact making element is positioned. Inone form of my invention, a spring contact member is rigidly attached atone of its ends to the interior surface of the upper plate, and itsopposite free end is normally biased by spring action to engage theother or lower plate. The free end of the contact spring is normallyheld out of engagement with the lower plate by soldering it to the innersurface of the upper plate. The current flowing through the spacerelement in response to lamp failure results in the development of asuicient amount of heat to melt the solder and thus release the contactspring to a circuit making position. In a modication of my invention,the Contact spring is held out of contact making engagement with thelower contact plate by a small bimetallic latch member which likewisefunctions to release the contact spring as a result of heat developed inthe spacer element as before.

Referring now to Figs. l and 2 which show the preferred embodiment of myinvention, it will be observed that one contact plate l0, which may betermed the upper plate, is in the form of a solid fiat disc, and theother contact plate, which may be termed the lower plate, is in the formof a nat bottomed cup Il having a bottom portion l2, and an upright orside portion i3.

As shown in Fig. 2, the spacer element for the contact plates is formedin two parts or blocks l5 and I6 spaced apart to provide a centralelongated cavity l1. These spacer blocks twithin the cup H, restingdirectly upon the bottom portion I2 of the cup, which in this instanceis the lower contact plate, and are tightly held therein by the upperplate l0 which may be secured in any suitable manner, such asA.millingand packingat a high temperature.

by crimping or otherwise forming the upper edge I8V of the side of thecup II as shown in Fig. 1.

The plates III and I2 may be insulated from each other by suitableinsulating material 2I, such as fish paper, which is placed within thecup II around the spacer blocks and bent over under the crimped portionvas shown in Fig. 1. It will be understood that this insulates thecontact plates from one another so that when a voltage is impressedacross the device, that is across the plates I and I2, the current mustflow through the spacer blocks I and I6.

The plates I0 and I2 may be formed of any suitable material, such ascopper, brass, etc., which is easily Worked or formed and which has goodelectrical qualities.

The spacer blocks I5 and I6 may be formed of non-linear conductingmaterials such as coppermaterial such as fused silicon carbide clay.This ...material .is Aof a ceramic nature and as formed by mixingsilicon carbide crystals with ball clay, The surfaces of the blocks aremade conducting by .spraying or.otherwise applying 'a suitable metalliccoating.

.This preferred material has a non-'linear con- -duction characteristicwhich providesfor greatly increasedcurrent flow as the voltageincreases. .Asanexampla the .current mightbe 5 milliamn peres,at..50volts,.20 milliamperes at 57 volts, and 3.amperes-,at'200 volts,depending upon'the exact v4characteristicof the material` which may bevaried .over an-.appreciable range of manufacture.

Theswitch or .contact making element of the deviceis in the vform of aat leaf spring 22 of .Phosphorbronza or the'like, having one end 23'.-rigidly vattached Vto the interior surface of the upper plate. Illbymeans of a rivet 24 or otherwise,

v and .its ,other or free end 25 attached `to this fsamefcontactplate bymeans of a small quantity of 50-50 solder-or the like as indicated at'26.in Fig. 1. It Ywill .be understood that the contact spring .22.is to.be held in a substantially flat posistion against the 4bottom surfaceyof the upper :contactplate I0 with its free end 25 out of en-;gagementiwith the bottom plate I2. The spring is so shapedor biasedthat when it is released 5 :by the'melting of ,the solder, thefree end25 will -.snap intofengagement with the contact plate I2 v`the-casingrformedxby the cup II and the upper :contact-plate |10.

.Iffdesired, the lower contact plate I2 may be .providedwth a smallopening 2`I directly. beneath vthe-freev end 25 of the --contact springso that a -fsuitable instrument may be inserted to push the freed endlof the-contactspring back to its normal l,position .once it has A.beenreleased. This makes itgpossible vto reset the cutout deviceto itsnormal .operating .condition by applying sufficient heat by :means of ra.soldering iron to the upper plate I0 .-toremelt .the solder 26 and thusagain detachably .secure'the free .end .25 of the contact spring totheaupper plate.

Referring .now to'Figs. 3 ,and 4 which show a V.modification of my.invention, it will be observed that in'this instance'the lower contactvnlate'3l 4 is in the form of a flat disc and the upper contact plate 32is formed as a shallow cup-shaped element of the same general shape, buthaving a circular indentation 33 which is clearly shown in Fig. 3.

In this instance the spacer element is in the form of a ring 34 and iscomprised of the same material as the spacer blocks I5 and I6 of thepreferred embodiment. The contact plates 3| and 32 may be securely heldin position on opposite sides of the spacer ring 34 in any suitable Inthis embodiment the contact spring 35 is mechanically controlled orreleased by means of a small mechanical latch 36 which may be formed ofbimetal. As shown best in Fig. 3, the contact spring 35 -is rigidlyattached by means of a rivet 31, or otherwise, to the upper surface ofthe contact plate 32, and is .provided at its free end 38 with a contact39 extending through a small 'opening 4I in the contact plate. yThiscontact Lspring is normally shaped orbiased so that vit moves down andcauses the contact element 39 to engage the lower plate 3 I.

The thermally responsive latch member 3B is shown best in Fig. 4. It maybe L-shaped and attached at'one end 42 vto the contact plate 32, and so'positioned with vrespect to the contact rspring-35 that its end portion43 normally engagesthecontact spring -andholdsit ina raisedvposition'with the contact member 3S out 4offengagement with the lowerplate 3I. Any other `suitable arrangement or shape of latchmay be used.

'It will be understood that, `in this instance, when thedevice issubjected to more than its normal operating voltage, the heat generatedby "current lowingthrough thespacer ring 3l! .will `cause the latch 36to release the contact spring Thev device may be reset forfurtheroperation bysimply raising the contact spring and re-engaging the end ofthe latch member 36 therewith.

In view of the foregoing detailed description lof the two-embodimentsof'my invention, it will "be apparent that I have provided a new type ofseriesy cutout device which vis in the form of a "positive'acting switchmechanism. The device,

in Veither of its two forms, is of a simplenaturc 'and isy economical to"manufacture and use. It is 'a-positive acting'device which may be usedover illustrative of the several different forms my invention may take.

I claim -as Vmy invention: n1. An electric cutout device comprising, two

-conducting surfaces, spacer means disposed in Acontact relationtherebetween, said spacer means being-formed of -a non-linearconductingmaterial, a movable 'contact member mounted onone of said surfaces,l athermally responsive lmeans normally retaining said contactmember in an'open; position, and operable to connect said Asurfaces together whenheated to a predetermined degree by current ow through said spacermeans. Y'

2. An electric cutout `device comprising, two conducting surfaces,spacer means disposed therebetween. saidv spacer means being'fcrmedl ofa non-linear conducting material and so shaped as to provide anelongated inner cavity, a movable contact -member mounted in said cavityoperable when in its closed position to connect said surfaces, andthermally responsive means normally retaining said contact member in anopen position and operable to release said contact member to its closedposition.

3. An electric cutout device for series lighting circuits and the likecomprising, a pair of spaced contact plates of conducting material, apair of spacer blocks disposed therebetween and in intimate contacttherewith, said blocks being formed of a non-linear conducting materialand being spaced apart to provide an elongated channel between theplates, and a contact spring mounted in said channel with one endrigidly secured to one plate and its opposite end soldered to the sameplate, whereby said other end is releasable by the melting of the solderand operable to engage the other plate.

4. An electric cutout device for series lighting circuits and the likecomprising, a pair of spaced contact plates of conducting material, aspacer ring of non-linear conducting material disposed therebetween, amovable contact element attached to one of said plates and biased intoengagement with the other plate, and a thermally responsive latchattached to said one plate for normally retaining said contact elementout of engagement with said other plate.

5. A cutout device for series lighting circuits and the like comprising,a cup-shaped member o conducting material having a flat bottom portion,a pair of spacer blocks of non-linear conducting material disposed insaid member, said spacer blocks being spaced apart to provide anelongated channel, a fiat disc-shaped member of conducting materialdisposed in the cup-shaped member over the spacer blocks with the upperedge of the cup-shaped member crimped over upon the disc to retain it inposition, insulation disposed between said cup-shaped member and thedisc, and a thermally responsive contact member disposed in said channelnormally engaging the disc-shaped member and operable in response to apredetermined rise in temperature resulting from the passage of electriccurrent through the spacer blocks to also engage the bottom of thecup-shaped member.

6. A cutout device for series lighting circuits and the like comprising,a pair of conducting members, spacer means interposed therebetween andin intimate contact therewith, said spacer means being formed of a fusedsilicon carbide clay having non-linear conducting characteristics, amovable contact member mounted on one of said surfaces and thermallyresponsive means normally retaining said contact member in an openposition, and releasing said movable contact member to engage bothsurfaces in response to the development of a predetermined amount ofheat in the spacer means as the result of current iow therethrough.

'7. A cutout device for series lighting circuits and the likecomprising, a pair of metallic plates, a pair of spacer blocksinterposed therebetween and held in intimate Contact relation therewith,said spacer blocks being so positioned relative to each other as to forma cavity between the plates and being formed of a fused silicon carbideclay, a contact spring rigidly attached at one end to one of said plateswithin the cavity and biased to engage the other plate with its freeend, and thermally responsive means mounted on said one platefunctioning to normally hold said free end of the contact spring out ofengagement with said other plate.

8. In an electric cutout device for series lighting circuits and thelike comprising, a pair of spaced contact plates, a spacer ring of fusedsilicon carbide clay interposed therebetween, one of said plates beingsubstantially flat and the other being shallow cup-shaped with a flatbottom portion extending downwardly within the ring and having anopening therein adjacent one side, a contact spring mounted within thecavity formed by the cupped plate with one end rigidly secured theretoand the other end carrying a contact member extending through saidopening in the bottom of the cupped plate, said contact spring beingnormally biased to cause said contact member to engage the fiat plate,and a bimetallic latch `member mounted on the cupshaped plate normallyfunctioning to hold the contact-spring in a retracted position andoperable in response to predetermined temperature conditions of thecutout to release the Contact spring.

FRANK W'. GODSEY, JR.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,795,741 Shoenberg et al. Mar.10, 1931 2,835,616 Shoenberg et al Dec. 8, 1931 1,898,174 Dubilier Feb.21, 1933 1,960,408 Brach May 29, 1934 1,971,194 McEachron et al. Aug.21, 1934 FOREIGN PATENTS Number Country Date 850,975 France Sept. 25,1939

